Here's an online version of your televison's (94 page) "Owner's Guide": http://www.mitsubishi-tv.com/pdf/ownersguides/WD-60735.pdf
It sounds like the lamp in your "Mitsubishi Lamp-Cartridge" blew.
If your TV remains under warranty, you'll want to call Mitsubishi at 1-800-553-7278, and you'll need to have (a) Mitsubishi Model number, (b) serial number, (c) TV purchase date, and you'll have to ship the old lamp module back to Mitsubishi so that: "All lamps replaced under warranty must be returned to Mitsubishi where they will be inspected for defect verification."
Return old Lamp-Cartridge to:
Mitsubishi Digital Electronics America 1001 Cherry Drive, Suite 2 Braselton, Georgia 30517
If you have trouble finding your TV's information, you need better "Warranty Management". Warranty Management can be done with software, or on paper. You may even choose to toss all your Owner's Manuals into a box, with the receipts. In case anything malfunctions/needs to be reprogrammed/reset then the manual & spare parts/cables (in a large Zip-Loc(R) baggie or two) can be quickly located and consulted.
If you television happens to be out of warranty, a nice (expensive) new lamp module can be ordered from Mitsubishi by calling 1-800-553-7278, or by ordering online at http://www.mitsuparts.com.
Refer to pages 75-76 of your Owner's Guide for complete Lamp-Cartridge module replacement instructions (with nice illustrations).
Your TV's Lamp-Cartridge part number is: Mitsubishi 915B403001
Here's an online source for the Mitsubishi 915B403001 Lamp-Cartridge: http://www.dlplamps.com/products/mitsubishi-dlp-lamp/mitsubishi-915b403001.html?gclid=CLzb6ciaiq0CFQdN4AodZkMonA
Note that with the dlplamps.com offerings, you can purchase the lamp only for $109, or the entire lamp-cartridge module for $129. So you can save yourself $20 if you're handy. Remember to keep all fingerprints off the lamp glass element - this small amount of oil will weaken the glass, and cause premature failure of the lamp. In the event that you get a fingerprint on the lamp glass, erase it thoroughly with rubbing alcohol. Alternatively, one may prevent fingerprints with latex gloves (make sure you haven't an allergy to latex, though).
If the reason that the lamp blew turns out to have been a clogged Lamp-Cartridge Filter (once you have the Lamp-Cartridge out of the TV and in your hand, you'll be able to easily see the mesh filter), then place a regular PM (Preventative Maintenance) of this filter on your calendar.
Answers & Comments
Televisions covered: Mitsubishi DLP High-Definition Televisions:
C Series: WD-60C8, WD-65C8, WD-73C8
735 Series: WD-60735, WD-65735, WD-73735
736 Series: WD-65736, WD-73736
835 Series: WD-65835, WD-73835
Here's an online version of your televison's (94 page) "Owner's Guide":
http://www.mitsubishi-tv.com/pdf/ownersguides/WD-60735.pdf
It sounds like the lamp in your "Mitsubishi Lamp-Cartridge" blew.
If your TV remains under warranty, you'll want to call Mitsubishi at 1-800-553-7278, and you'll need to have (a) Mitsubishi Model number, (b) serial number, (c) TV purchase date, and you'll have to ship the old lamp module back to Mitsubishi so that:
"All lamps replaced under warranty must be returned to Mitsubishi where they will be inspected for defect verification."
Return old Lamp-Cartridge to:
Mitsubishi Digital Electronics America
1001 Cherry Drive, Suite 2
Braselton, Georgia 30517
If you have trouble finding your TV's information, you need better "Warranty Management". Warranty Management can be done with software, or on paper. You may even choose to toss all your Owner's Manuals into a box, with the receipts. In case anything malfunctions/needs to be reprogrammed/reset then the manual & spare parts/cables (in a large Zip-Loc(R) baggie or two) can be quickly located and consulted.
If you television happens to be out of warranty, a nice (expensive) new lamp module can be ordered from Mitsubishi by calling 1-800-553-7278, or by ordering online at http://www.mitsuparts.com.
Refer to pages 75-76 of your Owner's Guide for complete Lamp-Cartridge module replacement instructions (with nice illustrations).
Your TV's Lamp-Cartridge part number is: Mitsubishi 915B403001
Here's an online source for the Mitsubishi 915B403001 Lamp-Cartridge:
http://www.dlplamps.com/products/mitsubishi-dlp-lamp/mitsubishi-915b403001.html?gclid=CLzb6ciaiq0CFQdN4AodZkMonA
Note that with the dlplamps.com offerings, you can purchase the lamp only for $109, or the entire lamp-cartridge module for $129. So you can save yourself $20 if you're handy. Remember to keep all fingerprints off the lamp glass element - this small amount of oil will weaken the glass, and cause premature failure of the lamp. In the event that you get a fingerprint on the lamp glass, erase it thoroughly with rubbing alcohol. Alternatively, one may prevent fingerprints with latex gloves (make sure you haven't an allergy to latex, though).
If the reason that the lamp blew turns out to have been a clogged Lamp-Cartridge Filter (once you have the Lamp-Cartridge out of the TV and in your hand, you'll be able to easily see the mesh filter), then place a regular PM (Preventative Maintenance) of this filter on your calendar.